Context:

Despite the efforts made on the ground, people continue to suffer with perennial flooding in north Bihar, Tarai in Nepal and nearby regions.

Relevance:

GS-III: Disaster and Management (Natural and Anthropogenic Disasters, Disaster Management in India), GS-I: Geography (Important Geophysical phenomena), GS-II: International Relations (India’s Neighbors, Foreign Policies affecting India’s Interests)

Mains Questions:

  1. The frequency of urban floods due to high intensity rainfall is increasing over the years. Discuss throwing light on the causes and impact of floods in India. (10 marks)
  2. Discuss the need for India and Nepal to re-establish water cooperation as a common cause and draw inspiration from the 1950s. (10 Marks)

Dimensions of the Article:

  1. What is a flood?
  2. Causes of floods in India
  3. Geographical distribution of floods in India
  4. What are the consequences of floods in India?
  5. Government’s efforts towards flood management
  6. About Increased Flood risks in Bihar and Nepal (Himalayan) region
  7. Measures to control floods in Himalayan Regions:
  8. History of Cooperation between Nepal and India regarding Floods

What is a flood?

Flood is Inundation of land and human settlements by the rise of water in the channels and its spill-over. Floods occur commonly when water in the form of surface run-off exceeds the carrying capacity of the river channels and streams and flows into the neighbouring low-lying flood plains.

Flood is a natural phenomenon but in recent times anthropogenic factors are becoming increasingly responsible for floods in India.

Causes of floods in India

Topographical and Hydrological factors:

  • Overflowing Rivers is the primary cause of floods in these regions. Brahmaputra and Barak and their tributaries in Assam and Kosi River in Bihar are responsible for majority of floods. The flooding situation in these rivers is often aggravated by:
    • erosion and silting of the river beds, resulting in a reduction of the carrying capacity of river channels
    • earthquakes and landslides leading to changes in river courses and obstructions to flow
    • synchronization of floods in the main and tributary rivers
    • inflow from neighboring states

Meteorological factors:

  • 80% of the precipitation in India takes place in the monsoon months from June to September. Concentrated rainfalls in a short span of time and events such as cloud bursts, glacial lake outbursts etc. often cause floods in Himalayan Rivers.

Anthropogenic factors:

  • These include deforestation, drainage congestion, encroachment of natural water bodies, unsustainable mining of river-bed, poorly planned development works and climate change induced extreme weather events.
  • Disturbances along the natural drainage channels and colonisation of flood-plains and river-beds is another major anthropogenic cause of floods.

Flaws in Flood management strategies:

  • Construction of embankments without proper assessment: Embankments have been used extensively in Assam and Bihar for managing flooded rivers. Some studies have concluded that in certain cases embankments have enhanced the flood problem.
  • Absence of an integrated approach by the Centre and the state: The Brahamaputra Board formed under the Brahmaputra Board Act, 1980, lacks coordination with the state government. Similar lack of coordination can be seen between the Assam Disaster Management Authority and National Disaster Management Authority (NDMA).
  • Unrealized potential of multipurpose dams: The dams in Assam and Bihar mainly focus at the hydropower benefits and lack storage space for flood control.
  • Trans boundary management of rivers: Absence of real time sharing of hydrological data and poor coordination among river basin nations about river flow management is an issue.

Geographical distribution of floods in India

  • Rashtriya Barh Ayog (National Flood Commission) identified 40 million hectares of land as flood-prone in India.
  • Historically, Bihar has been known to be India’s most flood-prone State. The Flood Management Improvement Support Centre (FMISC), Department of Water Resources, Government of Bihar estimates that 76% of the population in north Bihar faces the recurring threat of flood devastation.
  • Assam, West Bengal and Bihar are among the high flood-prone states of India.
  • Most of the rivers in the northern states like Punjab and Uttar Pradesh, are also vulnerable to occasional floods.
  • States like Rajasthan, Gujarat, Haryana and Punjab are also getting inundated in recent decades due to flash floods. This is partly because of the pattern of the monsoon and partly because of blocking of most of the streams and river channels by human activities.
  • Sometimes, Tamil Nadu experiences flooding during November – January due to the retreating monsoon.

What are the consequences of floods in India?

  • Frequent inundation of agricultural land and human settlement, particularly in Assam, West Bengal, Bihar and Eastern Uttar Pradesh (flooding rivers), coastal areas of Odisha, Andhra Pradesh, Tamil Nadu and Gujarat (cyclone) and Punjab, Rajasthan, Northern Gujarat and Haryana (flash floods) have serious consequences on the national economy and society.
  • Floods do not only destroy valuable crops every year but these also damage physical infrastructure such as roads, rails, bridges and human settlements.
  • Millions of people are rendered homeless and are also washed down along with their cattle in the floods.
  • Spread of diseases like cholera, gastro-enteritis, hepatitis and other water-borne diseases spread in the flood-affected areas.

Positive contribution:

  • Every year, floods deposit fertile silt over agricultural fields which is good for the crops. Majuli (Assam), the largest riverine island in the world, is the best example of good paddy crops after the annual floods in Brahmaputra.

Government’s efforts towards flood management

  • Rashtriya Barh Ayog (RBA) was constituted in 1976. It submitted its report in 1980 recommending various measures of flood control.
  • National Water Policy-2012: It emphasizes construction of large storage reservoirs and other non-structural measures for integrated flood management.
  • Setting up Ganga Flood Control Commission (GFCC) at Patna in 1972 and Brahmaputra Board in 1980 for advising the Ganga Basin States and North EasternStates respectively on Flood Management measures.
  • The Central Water Commission (CWC) was set up in 1945: It performs flood forecasting activities on major rivers and their tributaries in the country and issues flood forecast at 175 stations.

About Increased Flood risks in Bihar and Nepal (Himalayan) region

  • A large part of north Bihar, adjoining Nepal, is drained by a number of rivers that have their catchments in the steep and geologically nascent Himalayas.
  • Originating in Nepal, the high discharge and sediment load in the Kosi, Gandak, Burhi Gandak, Bagmati, Kamla Balan, Mahananda and Adhwara Group wreak havoc in the plains of Nepal’s Tarai and Bihar. About 65% of the catchment area of these rivers falls in Nepal/Tibet and only 35% of the catchment area lies in Bihar.
  • A study indicated that the plains of North Bihar have recorded the highest number of floods during the last 30-years. In the years 1978, 1987, 1998, 2004 and 2007, Bihar witnessed high magnitudes of flood.
  • Flood of 2004 demonstrates the severity of the flood problem when a vast area of almost 24 thousand Sq Km was badly affected by the floods of Bagmati, Kamla & Adhwara groups of rivers causing loss of about 800 human lives, even when Ganga, the master drain was flowing low.

Measures to control floods in Himalayan Regions:

Monitoring

  • The first step in tackling the threat from these glacial lakes is to start monitoring them and the glaciers more actively and regularly. We do not need to monitor every glacier.
  • Glaciers in one basin do not have remarkably different properties. If we identify one or two benchmark glaciers in every basin, those that are more easily accessible, and do detailed studies, then the results can be extrapolated to the rest of the glaciers in the basin or the state.
  • The government of Uttarakhand itself takes a lead in this effort, and not be entirely dependent on outside agencies for monitoring or data. Afterall, Uttarakhand is the most vulnerable to natural disasters like these, and it must build capacities to reduce the risk.

Planning

  • Construction-related activities in the state might not have a direct link to Sunday’s incident, but these are not entirely benign. The Himalayas are very young mountain systems, and extremely fragile.
  • A minor change in orientation of the rocks can be enough to trigger landslides. It is important to include glaciers in any environment impact assessment for major projects such as construction of dams.
  • The entire catchment areas should be made part of the impact assessment. In fact, project owners must be asked to invest in such studies. After all, their own assets are also at stake.

Mitigation

  • If we monitor the glaciers regularly, it would enable us to identify the lakes that need mitigation solutions. Several structural and geotechnical measures can be applied, and there are successful examples where the threat from these lakes have been reduced.
  • It is possible to construct channels for gradual and regulated discharge of water from these lakes, which will reduce the pressure on them, and minimise the chances of a breach.

History of Cooperation between Nepal and India regarding Floods

  • The history of cooperation between India and Nepal for embankments starting in the 1950s is worth looking at, which began when work on the Kosi embankments started in 1955 and a group of retired Nepali soldiers came over voluntarily to join hands with Indian volunteers and start the work.
  • Such a progressive government-citizen interface could not sustain itself and water cooperation between the two countries for a common cause waned.
  • Consequently, not much has happened barring the use of water resources for hydroelectric generation.
  • The Kosi Treaty of 1954, under which the embankments in Nepal were established and maintained, was not futuristic and did not make enough provisions for the maintenance of embankments and the rivers changing their course.
  • The deposition of stones, sand, silt and sediment has led to river beds rising, changing course and causing unimaginable losses. Between the mid-18th and mid-20th centuries, the Kosi is said to have shifted over 100 kilometres westward, resulting in large-scale human displacements. Also, there is a need for greater sensitisation on climatic imbalances and sustainable development.
  • Ironically, the same flood-affected regions also face the issue of drought and a sinking water table.
  • Clearly, course correction is needed to reestablish water cooperation as a common cause and draw inspiration for joint action from the 1950s.

-Source: The Hindu

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